I would suggest the mesh, as it helps to cover up my stretch marks. Ask your troupe if they would support you if you decided to wear one!
Cause hey its all about feeling good about yourself.

I don't see any reason you couldn't wear a mesh belly cover...if the rest have bare bellies, just get a nude/tan one (I think someone told me recently to get tan because the nude frequently looks white on stage, but don't take my word as gospel, ask when you're looking at 'em, or ask someone who has one...).

How long ago did you have your baby? It takes quite a while for stretch marks to fade (like months and months), but the redness does fade quite a bit and they become kind of silvery color and much thinner. I have some from my first pregnancy, and I was very self conscious about them too for quite a while. Then I just kind of stopped caring after a while...not sure why. Sometimes I think about it when I have to do 'up close' performances like in restaurants, but for stage shows it's really a visual non-issue, I think.
That said, I think I'm going to have quite a few more from my current pregnancy though, so I'll holler back atcha in a few months and maybe we'll be commiserating together (though I dearly hope you're not still self-conscious by then...). :)

Either way, if you're that concerned about it right now you should be able to talk to your troupemates about it. I'm not sure it's fair to ask everyone to wear belly-covers all the time (for my part, I find them *extremely* uncomfortable), but at least for some things you and they should be able to compromise. And again, I don't think you'd stick out from the line at all if you were wearing a skin-tone mesh cover, if it comes down to it.

Keep us posted!